The climate is changing rapidly and with it the challenges for construction. We not only have to protect the climate, but also adapt to the new conditions. But what do we need to adapt to?
A climate data analysis by the Federal Environment Agency and the EURAC research center looks at selected cities in different climate regions to illustrate what has already changed in a very short space of time. After analyzing weather data from 1986 to 2015, the researchers identified places that had similar values in the past, i.e. on average from 1960 to 1991, and called them “climatic twin cities”. Temperatures, precipitation and landscape were taken into account, as coastal climates change differently than mountain climates. For example, the climate in Hamburg today corresponds to that of Cologne at that time, while the “twin” for Stuttgart is Leiselsheim, located in the Upper Rhine region not far from the Kaiserstuhl.
In a future scenario without global climate protection measures (RCP 8.5), the “twin cities” are located even further south. According to this scenario, in the next decade, Stuttgart is expected to have a climate similar to that of Lyon. A few decades later, a climate like that of Toulouse can be expected. Further “climate twins” of German cities can be discovered here using an online tool.
The “twin cities” are only an approximation of the expected climate. The actual conditions depend on a complex interplay of local factors. Extreme weather events, for example, were not included in the analysis.
With a global perspective, a research team has carried out a similar comparative study for cities worldwide under the title “Understanding climate change from a global analysis of city analogues”. In this study, 520 major cities were examined to determine whether their climate in 2050 would be more similar to their own historical climate or to the historical climate of a major city in another bioclimatic region. The result: even in an optimistic climate scenario, three quarters of the cities studied will change so much that their climate will be more similar to that of another climate zone. For example, Seattle's climate will approach San Francisco's historical climate by 2050 and London's climate will develop in the direction of Barcelona. The study also shows that by 2050, one in five of the cities studied will have a climate that does not occur in any city today.
The climatic twin cities make it clear that the building sector needs to change fundamentally: not only do we need to minimize energy and resource consumption, we also need to adapt our strategies.
For us, this means modelling the future weather in different scenarios in our projects. From this, we develop holistic concepts that create a robust, comfortable and resource-efficient environment under the expected climatic conditions. In particular, we look at extreme cases such as heatwaves, but also possible synergies: adaptation strategies such as shading, increasing surface permeability and greening contribute to flood protection and reduce energy consumption for cooling, for example.